Thrombosis Prevention: Review of a New Mechanical Device

Clifford W. Colwell, Jr., MD

Thromboembolic disease is a common complication following total joint arthroplasty. Without prophylaxis, the rate of deep venous thrombosis after total hip arthroplasty is as high as 50%. Since it has been estimated that 90% of symptomatic pulmonary emboli originate from lower-extremity deep venous thrombi, prevention of these thrombi has become the standard of care after total hip arthroplasty. Mechanical methods of prophylaxis are often used for patients with a higher bleeding risk or as an adjunct to chemoprophylaxis. The use of mechanical compression devices for prophylaxis against deep venous thrombosis is an attractive option because it has minimal impact on postoperative hemostasis. Mechanical compression devices have been theorized to prevent clot formation by increasing venous blood flow from the legs, causing the release of endothelial-derived relaxing factors and causing release of urokinase. Mechanical compression has been associated with rare reports of compartment syndrome and peroneal nerve palsy. Bleeding rates with intermittent pneumatic compression devices are considered to be similar to those with placebos: about 4% after total hip arthroplasty. Two potential problems associated with compression devices -poor patient utilization and the peak venous velocity generated- are often the source of criticism leveled against their routine use. Widely available hospital-based compression devices prevent walking, are often difficult to apply, are quite challenging for the elderly to use, and tend to be bulky and uncomfortable. Devices that deliver higher peak venous velocity achieve it through rapid inflation of the compression sleeve by utilizing an air compression chamber in the pump unit. The rapid inflation often creates an annoying impact sensation on the patient's leg, further decreasing usage of the device. To overcome the problems of poor inpatient utilization and a lack of adaptability for home use and to achieve a high peak venous velocity without compromising patient utilization, a portable, battery-operated compression was developed. This compression device can be worn while the patient is in or out of bed with minimal inconvenience, can be applied easily by the patient, and can be sent home or to an extended-care facility with the patient for continuous use with compliance documented on a liquid crystal display screen in the device. In this JBJS/VJO video supplement to the article, Dr. Clifford W. Colwell, Jr., MD reviews the device.